Our aim will be to understand, to the best of our ability, the dynamic operation of two components of the nervous system. One, the synapse (Part I), is very basic to neural operation, constituting in fact a fundamental part of the fundamental unit. The other, the utricular receptor (Part II), is an organ specialized in detecting head accelerations, and this feature allows it to be sensitive to such important stimuli as orientation, with respect to gravity, and quasi-horizontal displacements. The understanding we are after is, in essence, the equivalent in the physiological field of what engineers call the "identification" of a system. Our efforts to identify each of these entities will be based upon the same formal approach of a "white noise" method where a random stimulus is imposed upon the preparation and some form of neuronal activity - trains of action potentials principally - are studied statistically. Our primary goal will be a description of the dynamic operation of the synapse and utricle; secondarily, we wish to be able to predict the neuronal response (postsynaptic or afferent) to any form of stimulus (presynaptic or accelerational), and further understand the basic (transmitter, ionic, molecular) events underlying the transfer.